Cylinder head



April 20, 1937. A. A. A. DARCHE CYLINDER HEAD Filed Dec. 51, 1935 Ill/ \\\rlllllllllfllll i atented Apr. 20, 1937 UNITED STATES PATENT OFFICE CYLINDER HEAD Albert Alexandre Augustin Darche, Bondy,

France Claims.

Gne of the difliculties encountered in the employment of cylinder heads consisting of light alloys is due to their high coefficient of expansion.

Because of this fact, important supplementary r) tensions or stresses are engendered when the cylinder heads are hot, these stresses amounting to about 5 kg. per square millimeter for each 100 degrees centigrade of the temperature rise.

In case of motors cooled by a circulating liquid, the total height of a cylinder head is equal approximately to from six to ten times the thickness of the inferior wall of the cylinder head.

ihe present invention takes account of this fact and one of its objects is to render entirely 3-: free the expansion of the whole part of the cylinder head situated above the inferior wall, owing to the feature that the cylinder head is fixed by tightening, not at its summit but directly against the inferior wall.

For convenience, the gudgeons or bolts for securing the head to the cylinder extend upwardly through the full height of the head in recesses or cavities in the head, and long tubular washers are placed on the bolts, which washers bear directly on the interior wall of the cylinder head and bear against the nuts which are on the bolts for tightening the head down.

If H is the total height of the tubular piece above the level of the cylinder and h the thickness of the inferior wall of the cylinder head, the supplementary tension, when the parts are hot, will be divided by the ratio if the tubular piece has the same coefiicient of expansion as the gudgeon and the same modulus of elasticity as the light alloy.

This twofold condition is nearly attained by the employment of cast iron, and, without any modification whatsoever of the general construction of the cylinder head, the supplementary tension when the parts are hot will be reduced 5 to 8 times in normal practice.

A circular space, provided concentrically around each gudgeon for the insertion of the tubular piece, is formed by a circular web stiffening and con solidating the cylinder head.

The invention enables one to reduce in very high degree the supplementary tension caused by the increase of the temperature.

Bearing in mind the fact that cast iron, the employment of which is preferred for the tubular piece, has a practical compression resistance equal approximately to twice that of light alloys, it is possible to reduce the transverse section of the tubular piece to a certain degree.

It is thereby possible to limit to 220 to 250 grams, per square millimeter, the supplementary tension produced by an increase of the temperature by degrees centigrade.

In the accompanying drawing:

Fig. 1 shows a part of the cylinder head in a vertical section through the passage of the bolt or gudgeon;

Figs. 2 and 3 show modifications of the tubular piece and illustrate how the thickness of the wall may be reduced in transverse section for a given length;

Fig. 4 is a plan view of a modification of the 15 invention;

Fig. 5 is a vertical section according to lines V-V of Fig. 4.

As shown in Fig. 1, concentrically to the gudgeon g and in the height of the cylinder head 20 there is provided a cylindrical space L open at the upper part of the cylinder head.

This space is formed, as hereinbefore stated, by a circular web stiffening and consolidating the cylinder head.

The tightening is effected against the inferior wall S of the cylinder head by means of the nut E screwed upon the upper threaded part of the gudgeon g.

The tubular piece T is inserted between the tightening nut E and the inferior wall S of the cylinder head, the fastening of which can be effected in the same Way as that of an ordinary cylinder head of cast iron, 5

It is obvious that above the inferior wall S the whole cylinder head is permitted free expansion in its height.

A suificient space is provided around the passage of the gudgeon across the thickness of the 40 wall S and around the tubular piece T, to permit of the free expansion of the cylinder head in its length and in its width.

Figs. 2 and 3 show, by way of example, two different embodiments of the tubular piece in longitudinal sectional views, illustrating a reduction in the transverse section of the same throughout a certain portion of the length of the tubular piece. 50

The invention permits of further modifications, for example with regard to the situation of the gudgeons fixing the cylinder head.

For example if the gudgeons are situated adjacent the border of the cylinder head, the space L 55 provided around the gudgeons may be open at one side. (See Figs. 4 and 5.)

The figures shown being simple explanatory diagrams, the relative dimensions represented are of course quite arbitrary.

Various other modifications of the invention may be made without departing from the spirit of the invention or the scope of the appended claims.

What I claim is:

1. In an internal combustion engine, a cylinder head having an inferior wall and a superior wall embracing between them a water-jacket, the cylinder head having a bolt hole in its inferior wall surrounded by a tubular web joining the inferior and superior walls and embracing a space of greater diameter than the bolt hole, which space extends from the interior wall to and through the superior wall, in combination with a cylinder having a bolt passing through said space and projecting beyond the superior wall of the cylinder head, a tubular member in said space of the cylinder head and surrounding said bolt, and a nut on said bolt for pressing said tubular member against the inferior wall of the cylinder head thereby to secure the cylinder head to the cylinder.

2. In an internal combustion engine, a cylinder and a cylinder head, said cylinder head comprising an inferior wall to lie against the cylinder, and an outer wall spaced therefrom to enclose a water-jacket, said cylinder head having a tubular web connecting theinferior and outer walls, said tubular web opening to the outside of the cylinder head and containing a chamber, the inferior wall of said cylinder head having a bolt hole communicating with said chamber, a bolt carried by the cylinder and passing through said bolt hole and said chamber, a tubular member within said chamber surrounding the bolt and projecting beyond the cylinder head, one end of said tubular member resting on said inferior wall within said chamber, and a nut on said bolt to engage the other end of said tubular member, for purposes described.

3 In an internal combustion engine, a cylinder and a cylinder head, a fastening bolt carried by said cylinder, said cylinder head having a passage through which said bolt projects, the cylinder head being hollow to constitute a Waterjacket, a sleeve on said bolt within said passage, said cylinder head having a wall directly engaging the cylinder against which wall one end of said sleeve rests, the other end of said sleeve projecting beyond the cylinder head, and a nut on said bolt to engage said other end of said sleeve, for purposes described.

l. In an internal combustion engine, a cylinder and a hollow cylinder head having a Wall to lie against the cylinder and having an outer wall spaced from said first mentioned wall and enclosing a water-jacket, a fastening bolt carried by said cylinder and passing through said cylinder head, and a sleeve and nut on said bolt for applying securing pressures directly to that wall of the cylinder head which lies against the cylinder, for purposes described.

5. In an internal combustion engine, a cylinder head having an inferior wall and a superior wall embracing between them' a Water-jacket, the cylinder head having'a bolt hole in its inferior wall surrounded by a tubular Web joining the inferior and superior walls and embracing a space of greater diameter than the bolt hole, which space extends from the inferior wall to and through the superior wall, in combination with a cylinder having a bolt passing through said space and projecting beyond the superior Wall of the cylinder head, a tubular member in said space of the cylinder head and surrounding said bolt, and a nut on said bolt for pressing said tubular member against the inferior wall of the cylinder head thereby to secure the cylinder head to the cylinder, said tubular member being transversely spaced from said bolt and from the adjacent parts of the cylinder head.

ALBERT ALEXANDRE AUGUSTIN DARCHE. 

